It has been recognized that incandescent lamps are a relatively inefficient light source. However, after more than a century of development and usage, they are cheap. Also, the public is quite familiar with the form factors and light output characteristics of such lamps. Fluorescent lamps have long been a more efficient alternative to incandescent lamps. For many years, fluorescent lamps were most commonly used in commercial settings. However, recently, compact fluorescent lamps have been developed as replacements for incandescent lamps. While more efficient than incandescent lamps, compact fluorescent lamps also have some drawbacks. For example, compact fluorescent lamps utilize mercury vapor and represent an environmental hazard if broken or at time of disposal. Cheaper versions of compact fluorescent lamps also do not provide as desirable a color characteristic of light output as traditional incandescent lamps and often differ extensively from traditional lamp form factors.
Recent years have seen a rapid expansion in the performance of solid state light emitting sources such as light emitting devices (LEDs). With improved performance, there has been an attendant expansion in the variety of applications for such devices. For example, rapid improvements in semiconductors and related manufacturing technologies are driving a trend in the lighting industry toward the use of light emitting diodes (LEDs) or other solid state light sources to produce light for general lighting applications to meet the need for more efficient lighting technologies and to address ever increasing costs of energy along with concerns about global warming due to consumption of fossil fuels to generate energy. LED solutions also are more environmentally friendly than competing technologies, such as compact fluorescent lamps, for replacements for traditional incandescent lamps. Hence, there are now a variety of products on the market and a wide range of published proposals for various types of lamps using solid state light emitting sources, as lamp replacement alternatives.
Increased output power of the solid state light emitting sources, however, increases the need to dissipate the heat generated by operation of the solid state light emitting sources. Although many different heat dissipation techniques have been developed, there is still room for further improvement for lamps for general lighting applications that utilize solid state light emitting sources, to effectively dissipate heat generated by operation of the solid state light emitting sources.